الفهرس 
GEOMORPHOLOGICAL, GEOLOGICAL, HYDROGEOLOGICAL GEOPHYSICAL SETTINGSOnly 14 pages are availabe for public view
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Abstract
The present study located in the southern part of Red Sea coastal area between latitude 25º to 25º 45` North and longitude 34º 15` to 35º East.. It includes five wadis; Um Gheig, Mubarak, Duber, Igla and Aalm. The water resources (groundwater or surface water) are considered as essential elements for the future development of this area. To evaluate the groundwater and testing the sites of the suggested dams, intensive field work of geoelectrical studies such as Vertical Electrical Sounding (1-D), two–dimensional electrical survey(2-D) and three-dimensional profiles (3-D)as well as the total land magnetic and geoseismic measurements were carried out along the main channel, tectonic plains and deltas.
Geomorphologically, the study area exhibits surface features of high and low relief, included three geomorphologic units. These units are; mountainous area, Red Sea coastal plain and hydrographic basins.
Stratigraphically, the southern part of the eastern desert, includes the study area, is occupied by rocks belonging to Pre-Cambrian basement rocks, Miocene and Quaternary deposits.
Structurally, the area is affected by fold and faults. The fold is plunging fold and the faults follow different trends. The NW-SE faults are most common in the area. These faults are of the normal type
Generally, the main aquifers in the study area are Quaternary wadi deposits, Miocene sediments and fractured basement rocks
Qualitative and Quantitative interpretations were carried out using the software for every type of data. The results of the Geophysical data indicate that, the geoelectrical sequence along the main channel consists of three geoelectrical zones (A, B&C). The sequence of these zones from top downwards is dry wadi deposits (zone A), zone (B) which is divided into two layers; saturated wadi deposits with brackish water (layer B1), saturated wadi deposits and Miocene sediments with saline water (layer B2) (in the eastern parts) and zone (C) is also divided into two layers; saturated fractured basement with brackish water (layer C1) and massive basement rocks (layer C2). On the other hand, the succession in the delta consists of three geoelectrical layers. These layers from top to base are, geoelectrical layer (A) which equivalent to the surface layer, geoelectrical layer (B) which equivalent to dry wadi deposits, geoelectrical layer (C) which represents the water-bearing formation in the delta. This layer is divided into two sub layers. The first one (C1) equivalents to wadi deposits saturated with brackish water and the second layer (C2) equivalents to wadi deposits and Miocene sediments saturated with saline water in the eastern parts as the results of sea water intrusion.
The present study explores two tectonic plains formed due to the effect of the structural faults. These tectonic plains along the main channels of wadi Duber and wadi Igla are promising to drill some wells.
The interpretation results of the integrated geophysical studies at the recommended sites for dam construction revealed that, the depth to the basement (bed rock) at the gate of the third tectonic plain of Wadi Um Gheig ranges from 11-13 m. Therefore, this site is suitable for constructing concrete dam that allows for storing water. On the other hand, the depth to the basement (bed rock) at the other sites is more than 25 m. Therefore, these sites are not suitable for constructing concrete dams where the bed rock has large depths, instead rock dams are recommended.
Generally, the depth to water decreases towards the east and the water level decreases towards the east i.e. the water flow toward the east.
The basement relief and the detected subsurface faults in the main wadis are confirmed from both the constructed geoelectrical and magnetic profiles.
The geologic structures play an important role on the groundwater occurrences through their effect on the thickness of the wadi deposits aquifer (zone B) in the main wadis.
There is a sea water intrusion in the deltas of some wadis such as delta wadi um Gheig, delta wadi Mubarak and delta wadi Duber as detected from the three dimensional of the geoelectrical survey and constructed Panel diagrams.
The water bearing layers (C1 &C2) suffer from seawater intrusion coming from the northeastern part; this intrusion is evidenced by the decrease of resistivity and the subsequent increase of salinity downward.
The resistivity decreases downwards in the wadi deposits water-bearing layers (C1 &C2), this is mainly attributed to the increase in clay content and/ or the increase in water salinity.
In deltas, the thickness of the brackish water layer increases from 4 to 26 m westwards , and the safe yield of the hand dug wells in the eastern parts varies from 42.5 to 85 m3/day.
The groundwater potentialities at the first tectonic plain of wadi Um Gheig is about 1,800,000 m3 as an example.